For most expensive posts, you're paying for the name brand. I have a Thomson on my brevet bike. There are other ovalized posts that have similar strength, and other 2-bolt posts with the same adjustability. They're even around the same weight... but
mine says Thomson on the side.
Similar to getting a Carradice saddlebag or a Berthoud frontbag instead of a Velo-Orange. They're all similar quality and styling.